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Global Warming

VIEWS: 3 PAGES: 38

									    Global Warming:
            &
 Strategies for overcoming
Greenhouse Gas Emissions
     What are Greenhouse Gases?
• GHG’s are the radiative force in the greenhouse
  effect: balancing the net radiation coming in and out
  of the atmosphere from the sun keeping the surface
  temp balanced

• Increasing concentrations of GHG’s warms the
  Earth’s atmosphere (Global Warming)

• Major GHG’s: ozone, water vapor, carbon dioxide,
  methane, nitrous oxide, and human made fluorinated
  gases

• Human influence on greenhouse effect is mainly
  through the release of CO2
                 Simple understanding of
                   Greenhouse Effect




http://www.msc.ec.gc.ca/education/scienceofclimatechange/understanding/greenhouse_gases/index_e.html
     Main Types of Greenhouse Gases
• Carbon Dioxide (CO2): burning of fossil fuels (oil, natural
  gases, and coal), decaying organic material, industrial by-
  products, deforestation

• Methane (CH4): production and transportation of fossil fuels,
  livestock, agricultural practices, and decay of organic waste

• Nitrous Oxide (N2O): agricultural and industrial activities and
  burning of fossil fuels and waste

• Fluorinated Gases (very strong synthetic gases): industrial
  processes, includes chlorofluorocarbons
       How Humans emit GHG
•   Burning of fossil fuels
•   Deforestation
•   Livestock Industry
•   Vented septic systems and landfills
•   Agricultural Activities
•   Use of Synthetic gases like
    chlorofluorocarbons in refrigerating
    systems and manufacturing processes
                        World CO2 Emissions
     from the Consumption and Flaring of Fossil Fuels 2005 in Million Metric Tons

• World Total: 28,192.74 MM tons

• USA: 5,956.98 MMtons
     • 21.2% of human emitted Carbon dioxide
     • 20.14 metric tons per capita

• Asia/Oceania: 10,362.49 MMtons
      • 36.8% of all Human emitted CO2,
      • BUT their per capita is only 2.87 metric tons

• USA CO2 emissions from
     • Petroleum: 2,613.96 million metric tons
     • Natural Gas: 1,201.37 million metric tons
     • Coal: 2,141.66 million metric tons

•   Stats from 2005, but posted in Sept. 2007 from EIA
     http://www.eia.doe.gov/environment.html
                    CO2 Emissions
• U.S. carbon dioxide emissions
  have grown by an average of 1.3
                                         North America
  percent annually since 1990
                                         Central and
                                         South America
• CO2 growth is mainly from              Europe

  population growth                      Middle East

                                         Africa
• Transportation sector is the largest
                                         Asia and
  source of CO2 emissions                Oceania


• Anthropogenic CO2 emissions
  total roughly 7 billion tons of
  Carbon a year.
http://tonto.eia.doe.gov/FTPROOT/environment/057304.pdf
                              Global Trends
                                                    • Kyoto Protocol is a way to
                                                      reduce GHG by regulations and
                                                      limits

                                                    • 174 parties who have ratified the
                                                      protocol

                                                    • 36 countries are required to
                                                      reduce GHG to specific levels


    •Six Kyoto GHG’s: carbon dioxide,               • The US is not apart of it! Some
    methane, nitrous oxide, sulful                    of the countries that ARE include
    hexafluoride, HFCs and PFCs                       the EU, Germany, Russia,
                                                      Romania, Iceland


http://www.mnp.nl/en/dossiers/Climatechange/TrendGHGemissions1990-2004.html
  US Greenhouse Gas Abatement Mapping Initiative
                Executive Report
• The USA abatement programs have been hypothesized to be “full
   blown” by 2030
Areas of Focus:
• Reducing Carbon Intensity of Electric Power
   – CCS, Wind, Nuclear, Solar Photovoltaics, Natural Gas-fired power
• Expanding and Enhancing Carbon Sinks
   –   Afforestation of pastureland and cropland
   –   Conservation tillage
   –   Forest management practices
   –   Winter Crop Covers
• Fuel Efficiency and Hybrid development
   – Biofuels (cellulosic)
   – Improving conventional vehicles
   – Hybrid and Plug-in Hybrid development
• Energy and Building Efficiency
   – Combined Heat and Power Application (CHP)
   – Residential Heat Power
     Strategies for Reducing GHG’s
• Research and Development of Renewable Energies
   – Solar Energy
   – Wind Energy
   – Biomass/Biofuel
   – Ocean (Wave and Tidal)
   – Hybrid systems
   – Fuel Cell Technology
   – Nuclear Energy
   – Higher Efficiency for Industries
   – Mixture of all!
• Clean Coal
• Carbon Capture and Sequestration
             What is Carbon Capture and
               Sequestration (CCS)?
•   CCS is the capturing of carbon dioxide from the atmosphere and
    emission streams and then storing it back in the Earth.

•   Estimates suggest that storage potential in geological formations of
    around 2000 GtCO2 (about 80 years of current global emissions)!


• 3-step process
  1. CO2 Capture from power plants, industrial sources
     and natural gas wells
  2. Compression and Transportation by pipeline or
     tankers
  3. Storage in Geological Reservoir Sequestration,
     Terrestrial Sequestration and Ocean Sequestration
                  Carbon Capture
• Capture is possible at different times and using
  different processes:
  – Before combustion (pre-combustion) 
    decarbonization of fossil fules
  – After Combustion (post-combustion)  capture from
    flue gas
• CO2 can be separated from the following during
  both pre and post combustion
  – Natural Gas
  – Flue gases from:
     •   SC-PCC plants (Supercritical Pulverised Coal Combustion
     •   SC-PCC with Oxyfuel Combustion
     •   IGCC plants (Integrated Coal Gasification Combined Cycle)
     •   NGCC plants (Natural Gas Combined Cycle)
       Pre-Combustion Capture
• Coal, or other fossil fuels, is gasified which converts the
  coal into a gaseous fuel by reacting it with high
  temperatures and certain amounts of oxygen.

• Through conversion it becomes a gas known as
  synthesis gas (syngas) which mainly consists of CO and
  H2 and the CO2 can be separated and captured

• A few ways to do this:
• IGCC Plants
• NGCC Plants
       Post Combustion Capture
• Chemically absorbing CO2 from flue gas in SC-PCC plants
  and NGCC plants using Amines and other chemical
  absorbents

• Oxyfuel combustion which produces almost pure CO2 that
  can be easily separated.

• Side note: Other separation methods such as membranes
  are being considered as a potential longer-term option for
  both pre/post combustion capture alone or in combination
  with other absorption techniques
  Plant Types:
Supercritical Pulverized Coal Combustion (SC-PCC)
• Pulverized coal combustion is the dominate coal generation in the US
  at the moment and uses very finely ground coal
• 37 % Net Energy Efficient
• HHV: 9,300 Btu/kWh

• Capture from Flue Gas:
   – captured by chemical absorbents that are heated to release CO2
     and regenerated. The high CO2 concentration is what facilitates
     the capture.
   – Amines are the common chemical absorbent
   – Energy required for solvent regeneration and CO2 compression
     are high
   – Efficiency losses are about 8-12 percentage points, with net
     efficiencies of about 35%
 SC-PCC with Carbon Capture by Oxyfuel Combustion
• Oxyfuel combustion is the process of burning coal with a gas mixture that
  is mainly oxygen instead of just using air.
    – 95% oxygen and the rest is recycled flue gas
    – The exhaust consists primarily of CO2 and H2O  great for CCS

• CO2 is captured by cooling and water condensation
• Avoids costly CO2 gas separation but creates an additional cost for the
  pure O2
• Net efficiency are similar to that of the SC-PCC capture from Flue gas
  (approx. 35%)
• Advantages:
   – About 75% less flue gas, leading to less heat being lost to the flue gas.
   – Suitable capture of CO2 for sequestration.
   – Less nitrogen oxide produced
   – Power Plants can be retrofit for this new process
   – Potentially lowers the cost for achieving a near net zero emissions
     from coal-based electricity generation
                                          http://www.ccsd.biz/factsheets/oxyfuel.cfm
http://www.aep.com/investors/present/documents/Bernstein-June-14-2007.pdf
                         IGCC Plants:
            Integrated Gasification Combined Cycle
• IGCC systems combine a coal gasification unit with a gas fired
  combined cycle power generation unit.

• Coal gasification: the process of converting coal to a gaseous fuel
  through partial oxidation. Carbon dioxide and Sulfur are removed

• The second part takes the cleaned gas and burns it in a conventional
  gas turbine to produce electrical energy

• Exhaust gas is recovered, used to boil water, creates steam for a steam
  turbine which also produces electrical energy.

• In typical plants, about 65% of the electrical energy is produced by the
  gas turbine and 35% by the steam turbine.

• 3 main basic types of coal gasifiers: Fluidised Bed, Fixed Bed, Entrained
  Flow


     •http://www.ccsd.biz/factsheets/igcc.cfm
                  IGCC continued….
Advantages:

•   achieves up to 50% thermal efficiency.
•   It uses 20-50% less water than a conventional coal power station.
•   It can utilize a variety of fuels, like heavy oils, petroleum cokes, and coals.
•   Up to 100% of the carbon dioxide can be captured and used for
    sequestrations
•   carbon capture is easier and costs less than capture from a pulverized coal
    plant
•   A minimum of 95% of the sulfur is removed
•   Nitrogen oxides (NOx) emissions are below 50ppm.
•   Syngas produced can be burned in a gas turbine for electricity generation, or
    used as a fuel in other applications, such as hydrogen-powered fuel cell
    vehicles


                            •http://www.ccsd.biz/factsheets/igcc.cfm
         IGCC Capture process
• The Syngas is sent to a shift reactor to convert CO into
  CO2 and further Hydrogen (H2).
• The process produces highly concentrated CO2 that is
  removable by physical absorbents
• H2 is then burned in a gas turbine (Hydrogen turbine
  needs more R&D)
• Another way: Oxyfuel Combustion with an IGCC plant to
  obtain CO2 for capture and storage.
• Possibly cheaper than post-combustion in SC-PCC
  plants
• But IGCC plants themselves are more expensive to build
  than SC-PCC plants
   CO2 Separation from Natural Gas
• Pre-Combustion: Natural gas is converted into H2
  and CO2 and the H2 is used for power generation and
  the CO2 is removed for storage.

• Post-Combustion: more difficult
  – This is because the CO2 concentration in the flue
    gas is lower (3-4%)
  – CO2 chemical absorption from NGCC flue gas is
    still done though
  – Plant efficiency is about 48-50%
  – Done in Norway and the UK
             Finally Sequestration (Storage)
•       Storage of CO2 in the Earth and there are MANY ways to do this!

•       Terrestrial : carbon is stored in land biomass (e.g. forests) or soils
    –      Ex: Soil management practices increase the amount of carbon a soil can
           take up
    –      Relatively low costs today in certain regions
    –      Disadvantages: small potential reservoirs involved, difficulties in
           monitoring and verification, not clear how long carbon can be effectively
           stored
•       Ocean : multiple approaches
    –      Increasing marine productivity in nutrient-limited regions
    –      Direct injection and storage of CO2 as a liquid phase on the sea floor
    –      Largest potential for storage and long time scales
    –      Concerns: potential impact on marine ecosystems and ocean acidification,
           CO2 eventual return to atmosphere
                 Geological Sequestration
•    CO2 is injected, at a supercritical phase into subsurface reservoirs
5 types of reservoirs
       Saline Aquifers: bodies of porous, permeable rock that hold brines.
           Could be largest reservoirs: potential to hold 100- 1,000 Gtons of C
           • Capacity in the US is large but incompletely mapped
           • Projects: Aquifers at Statoil’s Sleipner fields in the North Sea.

       Oil Shales: would be used for enhanced oil shale recovery
           using adsorption processes similar to those processes
           for coal.Still very uncertain: oil shales are very complex
            • Needs a lot of experiments to be sure of the
                capacity.
       Sealing: uses a cap rock, an impermeable rock layer that overlies a
          reservoir, to keep in the CO2. Poor seal, then CO2 will ultimately leak
          out.
           • Strength and composition of the seal rock under different
               injection pressures is very important.
           • Permeable faults and stratigraphic bodies may compromise the
               seal rock locally.
           • Experience and research needed.
  An illustration of how carbon dioxide is buried in a
  saline aquifer beneath the Sleipner West natural gas
  field in the North Sea. Photo courtesy of Statoil.
Demonstrating Carbon Sequestration Article Geotimes.org March 2003
     Geological Sequestration cont…
4.   Depleted Oil and Gas Fields: CO2 displaces pore fluids when
     injected into the depleted fields. Here hydrocarbons interact
     among the rock, brine and gas, mixing the CO2 with the oil
     causing its volume to expand. Some of the oil remains,
     sequestering much of the CO2 that dissolved in the oil, while the
     rest is recovered a.k.a. Enhanced Oil Recovery (EOR)
     –   Has been used for 25 yrs in the US and Canada.
     –   Lifetimes of many depleted fields could be significantly extended
     –   Problems: Brine acidification, Brine chemistry confusion could
         affect mineral precipitation, dissolution, and brine salinity and
         pH.
     –   Significant research and industrial experience is needed

     KEY: provides an incentive to store CO2 since it’s economically
         beneficial
     Places from Canada (Weyburn Oil Fields) to Algeria have been
     exploring EOR.
          Geological continued…
5.   Deep coal seams: A lot of coal is unmineable and has a seem
     around 2,500 ft deep.
     –   At this level, temps, and pressures, the CO2 adsorbs onto
         organic mineral surfaces and releases methane. This is enhanced
         Coal Bed Methane.
     –   Has potential to hold 220 billion tons of CO2.
     –    Injecting Nitrogen is also a possibility and has been tested in San
         Juan with BP (a mixture of both might be best!)
     –   Current Place: Allison Field development, New Mexico.
     –   This also provides more of an incentive to store CO2.
     –   Problems: More work is needed to understand how coal
         petrology affects the adsorption and release of gases.
         Difficult to see capacity.
                    Advanced Concepts
• Metal-organic framework compounds: “metal sponges”:
  honeycomb structures of metal and organic molecules that trap CO2
  in their pore spaces, it’s being researched at U of Michigan
• Genetic engineering: altering marine creatures to incorporate more
  carbon into shells or modifying methane-producing bacteria to grab
  more CO2 as their “food”.
• “Making Rocks”: CO2 (slightly acidic) reacts with rocks and soils and
  converts into other chemical forms. Process naturally takes to long!
   – Use magnesium silicates (rocks that include serpentine and olivine).
   – Magnesium silicate and CO2 together form carbonates and silicate such
     as sand.
   – Process is exothermic (producing heat).
   – Problem: Time. Magnesium silicate rocks reacting with only CO2 is a slow
     process. A stronger acid and heat are needed.
   – New Power Plants are needed: The Ohio group is working on a high-
     pressure, high-temp, 3-phase fluidized bed reactor (uses acids to dissolve
     serpentine in liquid CO2).
Advantages and Disadvantages of CCS

 • Disadvantages:
   – Risk of increasing Ocean Acidification and affecting Marine
     Ecosystems
   – Emissions of air pollutants increase due to energy used to
     capture CO2
   – Leakage Issues (monitoring, and estimating life-time)
   – Cost
   – Lots of needed capital investment
   – No regulatory framework created yet
 • Advantages:
   – Reduction of CO2 emissions by up to 90%
   – Oxyfuel process can significantly reduce NOx, Sox and PM
http://www.ipcc.ch/activity/srccs/SRCCS_Chapter9.pdf
       Costs and Outlook for CCS
• Costs:
   – Capture from combustion is more expensive and energy consuming
     than from Natural Gas Wells
   – Initial building costs for CCS power plants range from $.5 to 1
     billion
   – CCS in power plants range from $30 to 90 to 160/ton of CO2
     depending on technology.
   – Costs Include: capture, transportation and storage and monitoring
      varies greatly from technique to technique
   – EOR can off set some of these costs
   – Projected to fall below $25/tCO2 by 2030
• Potential:
   – May contribute 20% to 30% of the effort to reduce global emissions
     by 2050
   – Retrofitting existing plants for CCS already in progress
   – CCS use in biomass-fuelled power plants (net zero CO2)
   – Storage potential in geological formations of at least 2000 GtCO2
     which is equal to some 80 years of current global emissions
    Other ways to offset CO2 emissions
• Cogeneration: putting energy to use that would otherwise go
  to waste.
   – Ex: Lumber Mill using waste products like steam to do other
     work, like run a steam turbine to create electricity.
   – An energy two-for-one!

• Material Substitution: trying to make common materials using
  less energy-intensive processes or materials.
     – Changing all the lightbulbs in traffic lights  incandescent bulbs
       with LED

• Transportation Efficiency: Transportation accounts for almost
  one-third of all our energy use. There are many things we can
  do to decrease these emissions.
•   http://www.carboncounter.org/offset-your-emissions/personal-calculator.aspx
     – Calculate how much CO2 you emit!
                 Truck Stop Electrification
• Project Type: Transportation Efficiency, 15 year lifetime, starting 2005
• Offsets: 90,000 tons CO2: similar to taking 16,000 cars off the road for 1
  yr.
• Location: Oregon and Washington.

• Description: Every night truckers idle their diesel engines while they rest to
    power things like air conditioning or heat, and other appliances for their sleeper
    cabs. This idling causes wear on the machinery and also emits harmful pollutants
•   Shurepower’s shore-power truck electrified parking (STEP) system is a low cost
    alternative to idling that provides:
     – grid-based electricity, cable television and Internet connections to enable drivers
       to shut down their engines.
     – This option is cheaper than paying the for diesel fuel for
       an idle engine

• Non-GHG Benefits
     –   Reducing engine idling cleans the air
     –   Saves fossil fuel while saving truckers money
     –   Truckers sleep better without noise of engines
     –   Noise pollution is reduced for neighboring communities.
                                  http://www.climatetrust.org/offset_truckstop.php
                           Cool Climate Concrete
•   Project Type: Material Substitution, 5 year lifetime, starting Oct. 2004
•   Offsets: 250,000 tons CO2 like taking 49,801 cars off the road for 1 year
•   Location: Nation-wide
•   Description: Encourages the use of blended cement.
     – Manufacturing conventional cement releases about one ton of CO2 for
       every ton produced.
     – blended cement uses byproducts to replace parts of conventional
       cement: reduces carbon intensity while keeping structural integrity.

• Reducing CO2: Manufacturing of cement creates GHG’s when: 1) The
    cement kiln burns fossil fuels to make clinker and 2) the calcination process of
    cement clinker production.
     – Offsets occur at the point of blending
     – Accepted Supplementary Cementitious Materials (SCMs): ground
       granulated blast furnace slag, flyash, silica fume and rice hull ash.

    http://www.climatetrust.org/offset_concrete.php
        Ecuadorian Rainforest Restoration
•    Project Type: Sequestration
•    Offsets: 58,890 tons of CO2 similar to taking 11,731 cars off the road for 1 yr.
•    Project Lifetime: 99 years started March 2002 in Ecuador
•    Project Partners:
      – Jatun Sacha Foundation
      – Conservation International

Project Description: Less than 2% of Ecuador’s coastal
rainforests remains so Conservation International and
Jatun Sacha Foundation are reforesting about 680 acres
of the coastal rainforest in Ecuador that will hopefully
capture 65,000 tons of CO2 over the next century.
Reducing CO2: This project will restore and protect the land and allow it to grow
back to old growth forest.
    •Deforestation currently accounts for between 20 and 25 percent of annual
    human-induced CO2 emissions.

    * This location is one of Conservation International’s top five conservation
    targets worldwide and is one of the most biologically diverse areas on Earth!
              What can you do?!
• Set thermostat a degree higher for air-conditioning and a
  degree lower for heating or turn it down when you are not
  there/away
   – If every home in the US turned the dial we could save more than
     $10 billion per year on energy costs.
• Replace your light bulbs when they die with Compact
  Fluorescent bulbs
   – For each 27 watt compact fluorescent light bulb you’ll get carbon
     emission savings of 140 pounds per year and save $12.00
• Wash clothes in warm and cold water:
   – this will save 90% over the energy used when machine washing
     in hot water only.
• Fuel Efficient Cars: tires help too…
   – Keeping your tires fully inflated could improve your gas mileage
     by around 3%. The average American who drives 12,000 miles
     per year could save about 16 gallons of gasoline annually just by
     maintaining the tires.
     What can you do…continued
• Unplug your TV:
    – between 10%-15% of a TV’s energy is still used when its powered “off”. If
      every home unplugged their TV sets when they weren’t being used, we’d
      save more than $1 billion per year in energy costs.
• Conserve water by taking shorter showers, and turning off the tap
  while brushing your teeth:
    – Brushing teeth: you’ll conserve up to 5 gallons a day
    – Showers: every two min. you save, you can conserve more than 10
      gallons of water. If everyone in the US saves 1 gallon each day, over a
      year, it would equal TWICE the amount of freshwater withdrawn from the
      great lakes everyday!
• Buy rechargeable batteries:
    – A single rechargeable batter can replace up to 1,000 single use alkaline
      ones
• In Hotels re-use your towels and sheets:
    – The average hotel room consumes more than 200 gallons of water per
      day. Trimming the amount of water used they could save up to 40% of
      the a hotel’s water use.
• Use Energy Start appliances
• Plant a tree!
•   SOURCE: The Green Book by Elizabeth Rogers and Thomas M. Kostigen
                          Works Cited
•   http://www.portlandonline.com/osd/
•   http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html
•   http://www.epa.gov/climatechange/emissions/index.html
•   www.ecoaction.gc.ca
•   http://www.ec.gc.ca/pdb/ghg/ghg_home_e.cfm
•   http://www.ec.gc.ca/pdb/ghg/ghg_home_e.cfm
•   http://www.msc.ec.gc.ca/education/scienceofclimatechange/understanding/greenhous
    e_gases/index_e.html
•   http://www.ec.gc.ca/default.asp?lang=En&xml=FA0FF2F3-E389-483B-8D37-
    88EC993E5188
•   http://www2.nrcan.gc.ca/ES/OERD/english/View.asp?x=1324
•   http://www2.nrcan.gc.ca/ES/OERD/english/View.asp?x=1603
•   www.geotimes.org : S. Julio Friedmann, and geotimes staff
•   http://en.wikipedia.org/wiki/Carbon_dioxide_sink
•   http://www.ipcc.ch/activity/srccs/SRCCS_Chapter9.pdf
•   http://www.iea.org/Textbase/techno/essentials1.pdf
•   http://www.iea.org/Textbase/techno/iaresults.asp?id_ia=16
•   http://www.ieagreen.org.uk/
•   http://iea-ccs.fossil.energy.gov/
•   http://www.ccsd.biz/factsheets/oxyfuel.cfm
•   US Greenhouse Gas Abatement Mapping Initiative Executive Report Dec. 2007
    (Reducing Greenhouse Gas Emissions: How much at what cost? McKinsey &
    Company)
•   The Green Book by Elizabeth Rogers and Thomas M. Kostigen

								
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